试题详情
- 单项选择题 Examine the description of the EMPLOYEES table:
Which statement produces the number of different departments that have employees with last name Smith?（） A、SELECT COUNT(*) FROM employees WHERE last_name='Smith';
B、SELECT COUNT(dept_id) FROM employees WHERE last_name='Smith';
C、SELECT DISTINCT(COUNT(dept_id)) FROM employees WHERE last_name='Smith';
D、SELECT COUNT(DISTINCT dept_id) FROM employees WHERE last_name='Smith';
E、SELECT UNIQUE(dept_id) FROM employees WHERE last_name='Smith';
- D
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